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2108 lines
61 KiB
2108 lines
61 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
|
* eCryptfs: Linux filesystem encryption layer |
|
* |
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* Copyright (C) 1997-2004 Erez Zadok |
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* Copyright (C) 2001-2004 Stony Brook University |
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* Copyright (C) 2004-2007 International Business Machines Corp. |
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* Author(s): Michael A. Halcrow <[email protected]> |
|
* Michael C. Thompson <[email protected]> |
|
*/ |
|
|
|
#include <crypto/hash.h> |
|
#include <crypto/skcipher.h> |
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#include <linux/fs.h> |
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#include <linux/mount.h> |
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#include <linux/pagemap.h> |
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#include <linux/random.h> |
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#include <linux/compiler.h> |
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#include <linux/key.h> |
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#include <linux/namei.h> |
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#include <linux/file.h> |
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#include <linux/scatterlist.h> |
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#include <linux/slab.h> |
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#include <asm/unaligned.h> |
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#include <linux/kernel.h> |
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#include <linux/xattr.h> |
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#include "ecryptfs_kernel.h" |
|
|
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#define DECRYPT 0 |
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#define ENCRYPT 1 |
|
|
|
/** |
|
* ecryptfs_from_hex |
|
* @dst: Buffer to take the bytes from src hex; must be at least of |
|
* size (src_size / 2) |
|
* @src: Buffer to be converted from a hex string representation to raw value |
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* @dst_size: size of dst buffer, or number of hex characters pairs to convert |
|
*/ |
|
void ecryptfs_from_hex(char *dst, char *src, int dst_size) |
|
{ |
|
int x; |
|
char tmp[3] = { 0, }; |
|
|
|
for (x = 0; x < dst_size; x++) { |
|
tmp[0] = src[x * 2]; |
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tmp[1] = src[x * 2 + 1]; |
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dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16); |
|
} |
|
} |
|
|
|
/** |
|
* ecryptfs_calculate_md5 - calculates the md5 of @src |
|
* @dst: Pointer to 16 bytes of allocated memory |
|
* @crypt_stat: Pointer to crypt_stat struct for the current inode |
|
* @src: Data to be md5'd |
|
* @len: Length of @src |
|
* |
|
* Uses the allocated crypto context that crypt_stat references to |
|
* generate the MD5 sum of the contents of src. |
|
*/ |
|
static int ecryptfs_calculate_md5(char *dst, |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
char *src, int len) |
|
{ |
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int rc = crypto_shash_tfm_digest(crypt_stat->hash_tfm, src, len, dst); |
|
|
|
if (rc) { |
|
printk(KERN_ERR |
|
"%s: Error computing crypto hash; rc = [%d]\n", |
|
__func__, rc); |
|
goto out; |
|
} |
|
out: |
|
return rc; |
|
} |
|
|
|
static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name, |
|
char *cipher_name, |
|
char *chaining_modifier) |
|
{ |
|
int cipher_name_len = strlen(cipher_name); |
|
int chaining_modifier_len = strlen(chaining_modifier); |
|
int algified_name_len; |
|
int rc; |
|
|
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algified_name_len = (chaining_modifier_len + cipher_name_len + 3); |
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(*algified_name) = kmalloc(algified_name_len, GFP_KERNEL); |
|
if (!(*algified_name)) { |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
snprintf((*algified_name), algified_name_len, "%s(%s)", |
|
chaining_modifier, cipher_name); |
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rc = 0; |
|
out: |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_derive_iv |
|
* @iv: destination for the derived iv vale |
|
* @crypt_stat: Pointer to crypt_stat struct for the current inode |
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* @offset: Offset of the extent whose IV we are to derive |
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* |
|
* Generate the initialization vector from the given root IV and page |
|
* offset. |
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* |
|
* Returns zero on success; non-zero on error. |
|
*/ |
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int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat, |
|
loff_t offset) |
|
{ |
|
int rc = 0; |
|
char dst[MD5_DIGEST_SIZE]; |
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char src[ECRYPTFS_MAX_IV_BYTES + 16]; |
|
|
|
if (unlikely(ecryptfs_verbosity > 0)) { |
|
ecryptfs_printk(KERN_DEBUG, "root iv:\n"); |
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ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes); |
|
} |
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/* TODO: It is probably secure to just cast the least |
|
* significant bits of the root IV into an unsigned long and |
|
* add the offset to that rather than go through all this |
|
* hashing business. -Halcrow */ |
|
memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes); |
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memset((src + crypt_stat->iv_bytes), 0, 16); |
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snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset); |
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if (unlikely(ecryptfs_verbosity > 0)) { |
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ecryptfs_printk(KERN_DEBUG, "source:\n"); |
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ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16)); |
|
} |
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rc = ecryptfs_calculate_md5(dst, crypt_stat, src, |
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(crypt_stat->iv_bytes + 16)); |
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if (rc) { |
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ecryptfs_printk(KERN_WARNING, "Error attempting to compute " |
|
"MD5 while generating IV for a page\n"); |
|
goto out; |
|
} |
|
memcpy(iv, dst, crypt_stat->iv_bytes); |
|
if (unlikely(ecryptfs_verbosity > 0)) { |
|
ecryptfs_printk(KERN_DEBUG, "derived iv:\n"); |
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ecryptfs_dump_hex(iv, crypt_stat->iv_bytes); |
|
} |
|
out: |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_init_crypt_stat |
|
* @crypt_stat: Pointer to the crypt_stat struct to initialize. |
|
* |
|
* Initialize the crypt_stat structure. |
|
*/ |
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int ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
|
{ |
|
struct crypto_shash *tfm; |
|
int rc; |
|
|
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tfm = crypto_alloc_shash(ECRYPTFS_DEFAULT_HASH, 0, 0); |
|
if (IS_ERR(tfm)) { |
|
rc = PTR_ERR(tfm); |
|
ecryptfs_printk(KERN_ERR, "Error attempting to " |
|
"allocate crypto context; rc = [%d]\n", |
|
rc); |
|
return rc; |
|
} |
|
|
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memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
|
INIT_LIST_HEAD(&crypt_stat->keysig_list); |
|
mutex_init(&crypt_stat->keysig_list_mutex); |
|
mutex_init(&crypt_stat->cs_mutex); |
|
mutex_init(&crypt_stat->cs_tfm_mutex); |
|
crypt_stat->hash_tfm = tfm; |
|
crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED; |
|
|
|
return 0; |
|
} |
|
|
|
/** |
|
* ecryptfs_destroy_crypt_stat |
|
* @crypt_stat: Pointer to the crypt_stat struct to initialize. |
|
* |
|
* Releases all memory associated with a crypt_stat struct. |
|
*/ |
|
void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
|
{ |
|
struct ecryptfs_key_sig *key_sig, *key_sig_tmp; |
|
|
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crypto_free_skcipher(crypt_stat->tfm); |
|
crypto_free_shash(crypt_stat->hash_tfm); |
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list_for_each_entry_safe(key_sig, key_sig_tmp, |
|
&crypt_stat->keysig_list, crypt_stat_list) { |
|
list_del(&key_sig->crypt_stat_list); |
|
kmem_cache_free(ecryptfs_key_sig_cache, key_sig); |
|
} |
|
memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
|
} |
|
|
|
void ecryptfs_destroy_mount_crypt_stat( |
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struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
|
{ |
|
struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp; |
|
|
|
if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED)) |
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return; |
|
mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
|
list_for_each_entry_safe(auth_tok, auth_tok_tmp, |
|
&mount_crypt_stat->global_auth_tok_list, |
|
mount_crypt_stat_list) { |
|
list_del(&auth_tok->mount_crypt_stat_list); |
|
if (!(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID)) |
|
key_put(auth_tok->global_auth_tok_key); |
|
kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok); |
|
} |
|
mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
|
memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat)); |
|
} |
|
|
|
/** |
|
* virt_to_scatterlist |
|
* @addr: Virtual address |
|
* @size: Size of data; should be an even multiple of the block size |
|
* @sg: Pointer to scatterlist array; set to NULL to obtain only |
|
* the number of scatterlist structs required in array |
|
* @sg_size: Max array size |
|
* |
|
* Fills in a scatterlist array with page references for a passed |
|
* virtual address. |
|
* |
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* Returns the number of scatterlist structs in array used |
|
*/ |
|
int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg, |
|
int sg_size) |
|
{ |
|
int i = 0; |
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struct page *pg; |
|
int offset; |
|
int remainder_of_page; |
|
|
|
sg_init_table(sg, sg_size); |
|
|
|
while (size > 0 && i < sg_size) { |
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pg = virt_to_page(addr); |
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offset = offset_in_page(addr); |
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sg_set_page(&sg[i], pg, 0, offset); |
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remainder_of_page = PAGE_SIZE - offset; |
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if (size >= remainder_of_page) { |
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sg[i].length = remainder_of_page; |
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addr += remainder_of_page; |
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size -= remainder_of_page; |
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} else { |
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sg[i].length = size; |
|
addr += size; |
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size = 0; |
|
} |
|
i++; |
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} |
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if (size > 0) |
|
return -ENOMEM; |
|
return i; |
|
} |
|
|
|
struct extent_crypt_result { |
|
struct completion completion; |
|
int rc; |
|
}; |
|
|
|
static void extent_crypt_complete(struct crypto_async_request *req, int rc) |
|
{ |
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struct extent_crypt_result *ecr = req->data; |
|
|
|
if (rc == -EINPROGRESS) |
|
return; |
|
|
|
ecr->rc = rc; |
|
complete(&ecr->completion); |
|
} |
|
|
|
/** |
|
* crypt_scatterlist |
|
* @crypt_stat: Pointer to the crypt_stat struct to initialize. |
|
* @dst_sg: Destination of the data after performing the crypto operation |
|
* @src_sg: Data to be encrypted or decrypted |
|
* @size: Length of data |
|
* @iv: IV to use |
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* @op: ENCRYPT or DECRYPT to indicate the desired operation |
|
* |
|
* Returns the number of bytes encrypted or decrypted; negative value on error |
|
*/ |
|
static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, |
|
struct scatterlist *dst_sg, |
|
struct scatterlist *src_sg, int size, |
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unsigned char *iv, int op) |
|
{ |
|
struct skcipher_request *req = NULL; |
|
struct extent_crypt_result ecr; |
|
int rc = 0; |
|
|
|
if (unlikely(ecryptfs_verbosity > 0)) { |
|
ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n", |
|
crypt_stat->key_size); |
|
ecryptfs_dump_hex(crypt_stat->key, |
|
crypt_stat->key_size); |
|
} |
|
|
|
init_completion(&ecr.completion); |
|
|
|
mutex_lock(&crypt_stat->cs_tfm_mutex); |
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req = skcipher_request_alloc(crypt_stat->tfm, GFP_NOFS); |
|
if (!req) { |
|
mutex_unlock(&crypt_stat->cs_tfm_mutex); |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
|
|
skcipher_request_set_callback(req, |
|
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, |
|
extent_crypt_complete, &ecr); |
|
/* Consider doing this once, when the file is opened */ |
|
if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) { |
|
rc = crypto_skcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
|
crypt_stat->key_size); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, |
|
"Error setting key; rc = [%d]\n", |
|
rc); |
|
mutex_unlock(&crypt_stat->cs_tfm_mutex); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
crypt_stat->flags |= ECRYPTFS_KEY_SET; |
|
} |
|
mutex_unlock(&crypt_stat->cs_tfm_mutex); |
|
skcipher_request_set_crypt(req, src_sg, dst_sg, size, iv); |
|
rc = op == ENCRYPT ? crypto_skcipher_encrypt(req) : |
|
crypto_skcipher_decrypt(req); |
|
if (rc == -EINPROGRESS || rc == -EBUSY) { |
|
struct extent_crypt_result *ecr = req->base.data; |
|
|
|
wait_for_completion(&ecr->completion); |
|
rc = ecr->rc; |
|
reinit_completion(&ecr->completion); |
|
} |
|
out: |
|
skcipher_request_free(req); |
|
return rc; |
|
} |
|
|
|
/* |
|
* lower_offset_for_page |
|
* |
|
* Convert an eCryptfs page index into a lower byte offset |
|
*/ |
|
static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat, |
|
struct page *page) |
|
{ |
|
return ecryptfs_lower_header_size(crypt_stat) + |
|
((loff_t)page->index << PAGE_SHIFT); |
|
} |
|
|
|
/** |
|
* crypt_extent |
|
* @crypt_stat: crypt_stat containing cryptographic context for the |
|
* encryption operation |
|
* @dst_page: The page to write the result into |
|
* @src_page: The page to read from |
|
* @extent_offset: Page extent offset for use in generating IV |
|
* @op: ENCRYPT or DECRYPT to indicate the desired operation |
|
* |
|
* Encrypts or decrypts one extent of data. |
|
* |
|
* Return zero on success; non-zero otherwise |
|
*/ |
|
static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat, |
|
struct page *dst_page, |
|
struct page *src_page, |
|
unsigned long extent_offset, int op) |
|
{ |
|
pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index; |
|
loff_t extent_base; |
|
char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
|
struct scatterlist src_sg, dst_sg; |
|
size_t extent_size = crypt_stat->extent_size; |
|
int rc; |
|
|
|
extent_base = (((loff_t)page_index) * (PAGE_SIZE / extent_size)); |
|
rc = ecryptfs_derive_iv(extent_iv, crypt_stat, |
|
(extent_base + extent_offset)); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for " |
|
"extent [0x%.16llx]; rc = [%d]\n", |
|
(unsigned long long)(extent_base + extent_offset), rc); |
|
goto out; |
|
} |
|
|
|
sg_init_table(&src_sg, 1); |
|
sg_init_table(&dst_sg, 1); |
|
|
|
sg_set_page(&src_sg, src_page, extent_size, |
|
extent_offset * extent_size); |
|
sg_set_page(&dst_sg, dst_page, extent_size, |
|
extent_offset * extent_size); |
|
|
|
rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size, |
|
extent_iv, op); |
|
if (rc < 0) { |
|
printk(KERN_ERR "%s: Error attempting to crypt page with " |
|
"page_index = [%ld], extent_offset = [%ld]; " |
|
"rc = [%d]\n", __func__, page_index, extent_offset, rc); |
|
goto out; |
|
} |
|
rc = 0; |
|
out: |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_encrypt_page |
|
* @page: Page mapped from the eCryptfs inode for the file; contains |
|
* decrypted content that needs to be encrypted (to a temporary |
|
* page; not in place) and written out to the lower file |
|
* |
|
* Encrypt an eCryptfs page. This is done on a per-extent basis. Note |
|
* that eCryptfs pages may straddle the lower pages -- for instance, |
|
* if the file was created on a machine with an 8K page size |
|
* (resulting in an 8K header), and then the file is copied onto a |
|
* host with a 32K page size, then when reading page 0 of the eCryptfs |
|
* file, 24K of page 0 of the lower file will be read and decrypted, |
|
* and then 8K of page 1 of the lower file will be read and decrypted. |
|
* |
|
* Returns zero on success; negative on error |
|
*/ |
|
int ecryptfs_encrypt_page(struct page *page) |
|
{ |
|
struct inode *ecryptfs_inode; |
|
struct ecryptfs_crypt_stat *crypt_stat; |
|
char *enc_extent_virt; |
|
struct page *enc_extent_page = NULL; |
|
loff_t extent_offset; |
|
loff_t lower_offset; |
|
int rc = 0; |
|
|
|
ecryptfs_inode = page->mapping->host; |
|
crypt_stat = |
|
&(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); |
|
BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
|
enc_extent_page = alloc_page(GFP_USER); |
|
if (!enc_extent_page) { |
|
rc = -ENOMEM; |
|
ecryptfs_printk(KERN_ERR, "Error allocating memory for " |
|
"encrypted extent\n"); |
|
goto out; |
|
} |
|
|
|
for (extent_offset = 0; |
|
extent_offset < (PAGE_SIZE / crypt_stat->extent_size); |
|
extent_offset++) { |
|
rc = crypt_extent(crypt_stat, enc_extent_page, page, |
|
extent_offset, ENCRYPT); |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error encrypting extent; " |
|
"rc = [%d]\n", __func__, rc); |
|
goto out; |
|
} |
|
} |
|
|
|
lower_offset = lower_offset_for_page(crypt_stat, page); |
|
enc_extent_virt = kmap(enc_extent_page); |
|
rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset, |
|
PAGE_SIZE); |
|
kunmap(enc_extent_page); |
|
if (rc < 0) { |
|
ecryptfs_printk(KERN_ERR, |
|
"Error attempting to write lower page; rc = [%d]\n", |
|
rc); |
|
goto out; |
|
} |
|
rc = 0; |
|
out: |
|
if (enc_extent_page) { |
|
__free_page(enc_extent_page); |
|
} |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_decrypt_page |
|
* @page: Page mapped from the eCryptfs inode for the file; data read |
|
* and decrypted from the lower file will be written into this |
|
* page |
|
* |
|
* Decrypt an eCryptfs page. This is done on a per-extent basis. Note |
|
* that eCryptfs pages may straddle the lower pages -- for instance, |
|
* if the file was created on a machine with an 8K page size |
|
* (resulting in an 8K header), and then the file is copied onto a |
|
* host with a 32K page size, then when reading page 0 of the eCryptfs |
|
* file, 24K of page 0 of the lower file will be read and decrypted, |
|
* and then 8K of page 1 of the lower file will be read and decrypted. |
|
* |
|
* Returns zero on success; negative on error |
|
*/ |
|
int ecryptfs_decrypt_page(struct page *page) |
|
{ |
|
struct inode *ecryptfs_inode; |
|
struct ecryptfs_crypt_stat *crypt_stat; |
|
char *page_virt; |
|
unsigned long extent_offset; |
|
loff_t lower_offset; |
|
int rc = 0; |
|
|
|
ecryptfs_inode = page->mapping->host; |
|
crypt_stat = |
|
&(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); |
|
BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
|
|
|
lower_offset = lower_offset_for_page(crypt_stat, page); |
|
page_virt = kmap(page); |
|
rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE, |
|
ecryptfs_inode); |
|
kunmap(page); |
|
if (rc < 0) { |
|
ecryptfs_printk(KERN_ERR, |
|
"Error attempting to read lower page; rc = [%d]\n", |
|
rc); |
|
goto out; |
|
} |
|
|
|
for (extent_offset = 0; |
|
extent_offset < (PAGE_SIZE / crypt_stat->extent_size); |
|
extent_offset++) { |
|
rc = crypt_extent(crypt_stat, page, page, |
|
extent_offset, DECRYPT); |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error decrypting extent; " |
|
"rc = [%d]\n", __func__, rc); |
|
goto out; |
|
} |
|
} |
|
out: |
|
return rc; |
|
} |
|
|
|
#define ECRYPTFS_MAX_SCATTERLIST_LEN 4 |
|
|
|
/** |
|
* ecryptfs_init_crypt_ctx |
|
* @crypt_stat: Uninitialized crypt stats structure |
|
* |
|
* Initialize the crypto context. |
|
* |
|
* TODO: Performance: Keep a cache of initialized cipher contexts; |
|
* only init if needed |
|
*/ |
|
int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat) |
|
{ |
|
char *full_alg_name; |
|
int rc = -EINVAL; |
|
|
|
ecryptfs_printk(KERN_DEBUG, |
|
"Initializing cipher [%s]; strlen = [%d]; " |
|
"key_size_bits = [%zd]\n", |
|
crypt_stat->cipher, (int)strlen(crypt_stat->cipher), |
|
crypt_stat->key_size << 3); |
|
mutex_lock(&crypt_stat->cs_tfm_mutex); |
|
if (crypt_stat->tfm) { |
|
rc = 0; |
|
goto out_unlock; |
|
} |
|
rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, |
|
crypt_stat->cipher, "cbc"); |
|
if (rc) |
|
goto out_unlock; |
|
crypt_stat->tfm = crypto_alloc_skcipher(full_alg_name, 0, 0); |
|
if (IS_ERR(crypt_stat->tfm)) { |
|
rc = PTR_ERR(crypt_stat->tfm); |
|
crypt_stat->tfm = NULL; |
|
ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): " |
|
"Error initializing cipher [%s]\n", |
|
full_alg_name); |
|
goto out_free; |
|
} |
|
crypto_skcipher_set_flags(crypt_stat->tfm, |
|
CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); |
|
rc = 0; |
|
out_free: |
|
kfree(full_alg_name); |
|
out_unlock: |
|
mutex_unlock(&crypt_stat->cs_tfm_mutex); |
|
return rc; |
|
} |
|
|
|
static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat) |
|
{ |
|
int extent_size_tmp; |
|
|
|
crypt_stat->extent_mask = 0xFFFFFFFF; |
|
crypt_stat->extent_shift = 0; |
|
if (crypt_stat->extent_size == 0) |
|
return; |
|
extent_size_tmp = crypt_stat->extent_size; |
|
while ((extent_size_tmp & 0x01) == 0) { |
|
extent_size_tmp >>= 1; |
|
crypt_stat->extent_mask <<= 1; |
|
crypt_stat->extent_shift++; |
|
} |
|
} |
|
|
|
void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat) |
|
{ |
|
/* Default values; may be overwritten as we are parsing the |
|
* packets. */ |
|
crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE; |
|
set_extent_mask_and_shift(crypt_stat); |
|
crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES; |
|
if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
|
crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
|
else { |
|
if (PAGE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) |
|
crypt_stat->metadata_size = |
|
ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
|
else |
|
crypt_stat->metadata_size = PAGE_SIZE; |
|
} |
|
} |
|
|
|
/* |
|
* ecryptfs_compute_root_iv |
|
* |
|
* On error, sets the root IV to all 0's. |
|
*/ |
|
int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat) |
|
{ |
|
int rc = 0; |
|
char dst[MD5_DIGEST_SIZE]; |
|
|
|
BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE); |
|
BUG_ON(crypt_stat->iv_bytes <= 0); |
|
if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { |
|
rc = -EINVAL; |
|
ecryptfs_printk(KERN_WARNING, "Session key not valid; " |
|
"cannot generate root IV\n"); |
|
goto out; |
|
} |
|
rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key, |
|
crypt_stat->key_size); |
|
if (rc) { |
|
ecryptfs_printk(KERN_WARNING, "Error attempting to compute " |
|
"MD5 while generating root IV\n"); |
|
goto out; |
|
} |
|
memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes); |
|
out: |
|
if (rc) { |
|
memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes); |
|
crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING; |
|
} |
|
return rc; |
|
} |
|
|
|
static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat) |
|
{ |
|
get_random_bytes(crypt_stat->key, crypt_stat->key_size); |
|
crypt_stat->flags |= ECRYPTFS_KEY_VALID; |
|
ecryptfs_compute_root_iv(crypt_stat); |
|
if (unlikely(ecryptfs_verbosity > 0)) { |
|
ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n"); |
|
ecryptfs_dump_hex(crypt_stat->key, |
|
crypt_stat->key_size); |
|
} |
|
} |
|
|
|
/** |
|
* ecryptfs_copy_mount_wide_flags_to_inode_flags |
|
* @crypt_stat: The inode's cryptographic context |
|
* @mount_crypt_stat: The mount point's cryptographic context |
|
* |
|
* This function propagates the mount-wide flags to individual inode |
|
* flags. |
|
*/ |
|
static void ecryptfs_copy_mount_wide_flags_to_inode_flags( |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
|
{ |
|
if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) |
|
crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; |
|
if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) |
|
crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED; |
|
if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) { |
|
crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES; |
|
if (mount_crypt_stat->flags |
|
& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK) |
|
crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK; |
|
else if (mount_crypt_stat->flags |
|
& ECRYPTFS_GLOBAL_ENCFN_USE_FEK) |
|
crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK; |
|
} |
|
} |
|
|
|
static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs( |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
|
{ |
|
struct ecryptfs_global_auth_tok *global_auth_tok; |
|
int rc = 0; |
|
|
|
mutex_lock(&crypt_stat->keysig_list_mutex); |
|
mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
|
|
|
list_for_each_entry(global_auth_tok, |
|
&mount_crypt_stat->global_auth_tok_list, |
|
mount_crypt_stat_list) { |
|
if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK) |
|
continue; |
|
rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig); |
|
if (rc) { |
|
printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
} |
|
|
|
out: |
|
mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
|
mutex_unlock(&crypt_stat->keysig_list_mutex); |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_set_default_crypt_stat_vals |
|
* @crypt_stat: The inode's cryptographic context |
|
* @mount_crypt_stat: The mount point's cryptographic context |
|
* |
|
* Default values in the event that policy does not override them. |
|
*/ |
|
static void ecryptfs_set_default_crypt_stat_vals( |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
|
{ |
|
ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
|
mount_crypt_stat); |
|
ecryptfs_set_default_sizes(crypt_stat); |
|
strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER); |
|
crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES; |
|
crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID); |
|
crypt_stat->file_version = ECRYPTFS_FILE_VERSION; |
|
crypt_stat->mount_crypt_stat = mount_crypt_stat; |
|
} |
|
|
|
/** |
|
* ecryptfs_new_file_context |
|
* @ecryptfs_inode: The eCryptfs inode |
|
* |
|
* If the crypto context for the file has not yet been established, |
|
* this is where we do that. Establishing a new crypto context |
|
* involves the following decisions: |
|
* - What cipher to use? |
|
* - What set of authentication tokens to use? |
|
* Here we just worry about getting enough information into the |
|
* authentication tokens so that we know that they are available. |
|
* We associate the available authentication tokens with the new file |
|
* via the set of signatures in the crypt_stat struct. Later, when |
|
* the headers are actually written out, we may again defer to |
|
* userspace to perform the encryption of the session key; for the |
|
* foreseeable future, this will be the case with public key packets. |
|
* |
|
* Returns zero on success; non-zero otherwise |
|
*/ |
|
int ecryptfs_new_file_context(struct inode *ecryptfs_inode) |
|
{ |
|
struct ecryptfs_crypt_stat *crypt_stat = |
|
&ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
|
&ecryptfs_superblock_to_private( |
|
ecryptfs_inode->i_sb)->mount_crypt_stat; |
|
int cipher_name_len; |
|
int rc = 0; |
|
|
|
ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat); |
|
crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID); |
|
ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
|
mount_crypt_stat); |
|
rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat, |
|
mount_crypt_stat); |
|
if (rc) { |
|
printk(KERN_ERR "Error attempting to copy mount-wide key sigs " |
|
"to the inode key sigs; rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
cipher_name_len = |
|
strlen(mount_crypt_stat->global_default_cipher_name); |
|
memcpy(crypt_stat->cipher, |
|
mount_crypt_stat->global_default_cipher_name, |
|
cipher_name_len); |
|
crypt_stat->cipher[cipher_name_len] = '\0'; |
|
crypt_stat->key_size = |
|
mount_crypt_stat->global_default_cipher_key_size; |
|
ecryptfs_generate_new_key(crypt_stat); |
|
rc = ecryptfs_init_crypt_ctx(crypt_stat); |
|
if (rc) |
|
ecryptfs_printk(KERN_ERR, "Error initializing cryptographic " |
|
"context for cipher [%s]: rc = [%d]\n", |
|
crypt_stat->cipher, rc); |
|
out: |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_validate_marker - check for the ecryptfs marker |
|
* @data: The data block in which to check |
|
* |
|
* Returns zero if marker found; -EINVAL if not found |
|
*/ |
|
static int ecryptfs_validate_marker(char *data) |
|
{ |
|
u32 m_1, m_2; |
|
|
|
m_1 = get_unaligned_be32(data); |
|
m_2 = get_unaligned_be32(data + 4); |
|
if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2) |
|
return 0; |
|
ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; " |
|
"MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2, |
|
MAGIC_ECRYPTFS_MARKER); |
|
ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = " |
|
"[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER)); |
|
return -EINVAL; |
|
} |
|
|
|
struct ecryptfs_flag_map_elem { |
|
u32 file_flag; |
|
u32 local_flag; |
|
}; |
|
|
|
/* Add support for additional flags by adding elements here. */ |
|
static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = { |
|
{0x00000001, ECRYPTFS_ENABLE_HMAC}, |
|
{0x00000002, ECRYPTFS_ENCRYPTED}, |
|
{0x00000004, ECRYPTFS_METADATA_IN_XATTR}, |
|
{0x00000008, ECRYPTFS_ENCRYPT_FILENAMES} |
|
}; |
|
|
|
/** |
|
* ecryptfs_process_flags |
|
* @crypt_stat: The cryptographic context |
|
* @page_virt: Source data to be parsed |
|
* @bytes_read: Updated with the number of bytes read |
|
*/ |
|
static void ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat, |
|
char *page_virt, int *bytes_read) |
|
{ |
|
int i; |
|
u32 flags; |
|
|
|
flags = get_unaligned_be32(page_virt); |
|
for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++) |
|
if (flags & ecryptfs_flag_map[i].file_flag) { |
|
crypt_stat->flags |= ecryptfs_flag_map[i].local_flag; |
|
} else |
|
crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag); |
|
/* Version is in top 8 bits of the 32-bit flag vector */ |
|
crypt_stat->file_version = ((flags >> 24) & 0xFF); |
|
(*bytes_read) = 4; |
|
} |
|
|
|
/** |
|
* write_ecryptfs_marker |
|
* @page_virt: The pointer to in a page to begin writing the marker |
|
* @written: Number of bytes written |
|
* |
|
* Marker = 0x3c81b7f5 |
|
*/ |
|
static void write_ecryptfs_marker(char *page_virt, size_t *written) |
|
{ |
|
u32 m_1, m_2; |
|
|
|
get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); |
|
m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER); |
|
put_unaligned_be32(m_1, page_virt); |
|
page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2); |
|
put_unaligned_be32(m_2, page_virt); |
|
(*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
|
} |
|
|
|
void ecryptfs_write_crypt_stat_flags(char *page_virt, |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
size_t *written) |
|
{ |
|
u32 flags = 0; |
|
int i; |
|
|
|
for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++) |
|
if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag) |
|
flags |= ecryptfs_flag_map[i].file_flag; |
|
/* Version is in top 8 bits of the 32-bit flag vector */ |
|
flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000); |
|
put_unaligned_be32(flags, page_virt); |
|
(*written) = 4; |
|
} |
|
|
|
struct ecryptfs_cipher_code_str_map_elem { |
|
char cipher_str[16]; |
|
u8 cipher_code; |
|
}; |
|
|
|
/* Add support for additional ciphers by adding elements here. The |
|
* cipher_code is whatever OpenPGP applications use to identify the |
|
* ciphers. List in order of probability. */ |
|
static struct ecryptfs_cipher_code_str_map_elem |
|
ecryptfs_cipher_code_str_map[] = { |
|
{"aes",RFC2440_CIPHER_AES_128 }, |
|
{"blowfish", RFC2440_CIPHER_BLOWFISH}, |
|
{"des3_ede", RFC2440_CIPHER_DES3_EDE}, |
|
{"cast5", RFC2440_CIPHER_CAST_5}, |
|
{"twofish", RFC2440_CIPHER_TWOFISH}, |
|
{"cast6", RFC2440_CIPHER_CAST_6}, |
|
{"aes", RFC2440_CIPHER_AES_192}, |
|
{"aes", RFC2440_CIPHER_AES_256} |
|
}; |
|
|
|
/** |
|
* ecryptfs_code_for_cipher_string |
|
* @cipher_name: The string alias for the cipher |
|
* @key_bytes: Length of key in bytes; used for AES code selection |
|
* |
|
* Returns zero on no match, or the cipher code on match |
|
*/ |
|
u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes) |
|
{ |
|
int i; |
|
u8 code = 0; |
|
struct ecryptfs_cipher_code_str_map_elem *map = |
|
ecryptfs_cipher_code_str_map; |
|
|
|
if (strcmp(cipher_name, "aes") == 0) { |
|
switch (key_bytes) { |
|
case 16: |
|
code = RFC2440_CIPHER_AES_128; |
|
break; |
|
case 24: |
|
code = RFC2440_CIPHER_AES_192; |
|
break; |
|
case 32: |
|
code = RFC2440_CIPHER_AES_256; |
|
} |
|
} else { |
|
for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) |
|
if (strcmp(cipher_name, map[i].cipher_str) == 0) { |
|
code = map[i].cipher_code; |
|
break; |
|
} |
|
} |
|
return code; |
|
} |
|
|
|
/** |
|
* ecryptfs_cipher_code_to_string |
|
* @str: Destination to write out the cipher name |
|
* @cipher_code: The code to convert to cipher name string |
|
* |
|
* Returns zero on success |
|
*/ |
|
int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code) |
|
{ |
|
int rc = 0; |
|
int i; |
|
|
|
str[0] = '\0'; |
|
for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) |
|
if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code) |
|
strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str); |
|
if (str[0] == '\0') { |
|
ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: " |
|
"[%d]\n", cipher_code); |
|
rc = -EINVAL; |
|
} |
|
return rc; |
|
} |
|
|
|
int ecryptfs_read_and_validate_header_region(struct inode *inode) |
|
{ |
|
u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
|
u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; |
|
int rc; |
|
|
|
rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES, |
|
inode); |
|
if (rc < 0) |
|
return rc; |
|
else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) |
|
return -EINVAL; |
|
rc = ecryptfs_validate_marker(marker); |
|
if (!rc) |
|
ecryptfs_i_size_init(file_size, inode); |
|
return rc; |
|
} |
|
|
|
void |
|
ecryptfs_write_header_metadata(char *virt, |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
size_t *written) |
|
{ |
|
u32 header_extent_size; |
|
u16 num_header_extents_at_front; |
|
|
|
header_extent_size = (u32)crypt_stat->extent_size; |
|
num_header_extents_at_front = |
|
(u16)(crypt_stat->metadata_size / crypt_stat->extent_size); |
|
put_unaligned_be32(header_extent_size, virt); |
|
virt += 4; |
|
put_unaligned_be16(num_header_extents_at_front, virt); |
|
(*written) = 6; |
|
} |
|
|
|
struct kmem_cache *ecryptfs_header_cache; |
|
|
|
/** |
|
* ecryptfs_write_headers_virt |
|
* @page_virt: The virtual address to write the headers to |
|
* @max: The size of memory allocated at page_virt |
|
* @size: Set to the number of bytes written by this function |
|
* @crypt_stat: The cryptographic context |
|
* @ecryptfs_dentry: The eCryptfs dentry |
|
* |
|
* Format version: 1 |
|
* |
|
* Header Extent: |
|
* Octets 0-7: Unencrypted file size (big-endian) |
|
* Octets 8-15: eCryptfs special marker |
|
* Octets 16-19: Flags |
|
* Octet 16: File format version number (between 0 and 255) |
|
* Octets 17-18: Reserved |
|
* Octet 19: Bit 1 (lsb): Reserved |
|
* Bit 2: Encrypted? |
|
* Bits 3-8: Reserved |
|
* Octets 20-23: Header extent size (big-endian) |
|
* Octets 24-25: Number of header extents at front of file |
|
* (big-endian) |
|
* Octet 26: Begin RFC 2440 authentication token packet set |
|
* Data Extent 0: |
|
* Lower data (CBC encrypted) |
|
* Data Extent 1: |
|
* Lower data (CBC encrypted) |
|
* ... |
|
* |
|
* Returns zero on success |
|
*/ |
|
static int ecryptfs_write_headers_virt(char *page_virt, size_t max, |
|
size_t *size, |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
struct dentry *ecryptfs_dentry) |
|
{ |
|
int rc; |
|
size_t written; |
|
size_t offset; |
|
|
|
offset = ECRYPTFS_FILE_SIZE_BYTES; |
|
write_ecryptfs_marker((page_virt + offset), &written); |
|
offset += written; |
|
ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat, |
|
&written); |
|
offset += written; |
|
ecryptfs_write_header_metadata((page_virt + offset), crypt_stat, |
|
&written); |
|
offset += written; |
|
rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat, |
|
ecryptfs_dentry, &written, |
|
max - offset); |
|
if (rc) |
|
ecryptfs_printk(KERN_WARNING, "Error generating key packet " |
|
"set; rc = [%d]\n", rc); |
|
if (size) { |
|
offset += written; |
|
*size = offset; |
|
} |
|
return rc; |
|
} |
|
|
|
static int |
|
ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode, |
|
char *virt, size_t virt_len) |
|
{ |
|
int rc; |
|
|
|
rc = ecryptfs_write_lower(ecryptfs_inode, virt, |
|
0, virt_len); |
|
if (rc < 0) |
|
printk(KERN_ERR "%s: Error attempting to write header " |
|
"information to lower file; rc = [%d]\n", __func__, rc); |
|
else |
|
rc = 0; |
|
return rc; |
|
} |
|
|
|
static int |
|
ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry, |
|
struct inode *ecryptfs_inode, |
|
char *page_virt, size_t size) |
|
{ |
|
int rc; |
|
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); |
|
struct inode *lower_inode = d_inode(lower_dentry); |
|
|
|
if (!(lower_inode->i_opflags & IOP_XATTR)) { |
|
rc = -EOPNOTSUPP; |
|
goto out; |
|
} |
|
|
|
inode_lock(lower_inode); |
|
rc = __vfs_setxattr(&init_user_ns, lower_dentry, lower_inode, |
|
ECRYPTFS_XATTR_NAME, page_virt, size, 0); |
|
if (!rc && ecryptfs_inode) |
|
fsstack_copy_attr_all(ecryptfs_inode, lower_inode); |
|
inode_unlock(lower_inode); |
|
out: |
|
return rc; |
|
} |
|
|
|
static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask, |
|
unsigned int order) |
|
{ |
|
struct page *page; |
|
|
|
page = alloc_pages(gfp_mask | __GFP_ZERO, order); |
|
if (page) |
|
return (unsigned long) page_address(page); |
|
return 0; |
|
} |
|
|
|
/** |
|
* ecryptfs_write_metadata |
|
* @ecryptfs_dentry: The eCryptfs dentry, which should be negative |
|
* @ecryptfs_inode: The newly created eCryptfs inode |
|
* |
|
* Write the file headers out. This will likely involve a userspace |
|
* callout, in which the session key is encrypted with one or more |
|
* public keys and/or the passphrase necessary to do the encryption is |
|
* retrieved via a prompt. Exactly what happens at this point should |
|
* be policy-dependent. |
|
* |
|
* Returns zero on success; non-zero on error |
|
*/ |
|
int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry, |
|
struct inode *ecryptfs_inode) |
|
{ |
|
struct ecryptfs_crypt_stat *crypt_stat = |
|
&ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
|
unsigned int order; |
|
char *virt; |
|
size_t virt_len; |
|
size_t size = 0; |
|
int rc = 0; |
|
|
|
if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
|
if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { |
|
printk(KERN_ERR "Key is invalid; bailing out\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
} else { |
|
printk(KERN_WARNING "%s: Encrypted flag not set\n", |
|
__func__); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
virt_len = crypt_stat->metadata_size; |
|
order = get_order(virt_len); |
|
/* Released in this function */ |
|
virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order); |
|
if (!virt) { |
|
printk(KERN_ERR "%s: Out of memory\n", __func__); |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
/* Zeroed page ensures the in-header unencrypted i_size is set to 0 */ |
|
rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat, |
|
ecryptfs_dentry); |
|
if (unlikely(rc)) { |
|
printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n", |
|
__func__, rc); |
|
goto out_free; |
|
} |
|
if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
|
rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode, |
|
virt, size); |
|
else |
|
rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt, |
|
virt_len); |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error writing metadata out to lower file; " |
|
"rc = [%d]\n", __func__, rc); |
|
goto out_free; |
|
} |
|
out_free: |
|
free_pages((unsigned long)virt, order); |
|
out: |
|
return rc; |
|
} |
|
|
|
#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0 |
|
#define ECRYPTFS_VALIDATE_HEADER_SIZE 1 |
|
static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat, |
|
char *virt, int *bytes_read, |
|
int validate_header_size) |
|
{ |
|
int rc = 0; |
|
u32 header_extent_size; |
|
u16 num_header_extents_at_front; |
|
|
|
header_extent_size = get_unaligned_be32(virt); |
|
virt += sizeof(__be32); |
|
num_header_extents_at_front = get_unaligned_be16(virt); |
|
crypt_stat->metadata_size = (((size_t)num_header_extents_at_front |
|
* (size_t)header_extent_size)); |
|
(*bytes_read) = (sizeof(__be32) + sizeof(__be16)); |
|
if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE) |
|
&& (crypt_stat->metadata_size |
|
< ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) { |
|
rc = -EINVAL; |
|
printk(KERN_WARNING "Invalid header size: [%zd]\n", |
|
crypt_stat->metadata_size); |
|
} |
|
return rc; |
|
} |
|
|
|
/** |
|
* set_default_header_data |
|
* @crypt_stat: The cryptographic context |
|
* |
|
* For version 0 file format; this function is only for backwards |
|
* compatibility for files created with the prior versions of |
|
* eCryptfs. |
|
*/ |
|
static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat) |
|
{ |
|
crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
|
} |
|
|
|
void ecryptfs_i_size_init(const char *page_virt, struct inode *inode) |
|
{ |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat; |
|
struct ecryptfs_crypt_stat *crypt_stat; |
|
u64 file_size; |
|
|
|
crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; |
|
mount_crypt_stat = |
|
&ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat; |
|
if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { |
|
file_size = i_size_read(ecryptfs_inode_to_lower(inode)); |
|
if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
|
file_size += crypt_stat->metadata_size; |
|
} else |
|
file_size = get_unaligned_be64(page_virt); |
|
i_size_write(inode, (loff_t)file_size); |
|
crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED; |
|
} |
|
|
|
/** |
|
* ecryptfs_read_headers_virt |
|
* @page_virt: The virtual address into which to read the headers |
|
* @crypt_stat: The cryptographic context |
|
* @ecryptfs_dentry: The eCryptfs dentry |
|
* @validate_header_size: Whether to validate the header size while reading |
|
* |
|
* Read/parse the header data. The header format is detailed in the |
|
* comment block for the ecryptfs_write_headers_virt() function. |
|
* |
|
* Returns zero on success |
|
*/ |
|
static int ecryptfs_read_headers_virt(char *page_virt, |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
struct dentry *ecryptfs_dentry, |
|
int validate_header_size) |
|
{ |
|
int rc = 0; |
|
int offset; |
|
int bytes_read; |
|
|
|
ecryptfs_set_default_sizes(crypt_stat); |
|
crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private( |
|
ecryptfs_dentry->d_sb)->mount_crypt_stat; |
|
offset = ECRYPTFS_FILE_SIZE_BYTES; |
|
rc = ecryptfs_validate_marker(page_virt + offset); |
|
if (rc) |
|
goto out; |
|
if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED)) |
|
ecryptfs_i_size_init(page_virt, d_inode(ecryptfs_dentry)); |
|
offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
|
ecryptfs_process_flags(crypt_stat, (page_virt + offset), &bytes_read); |
|
if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) { |
|
ecryptfs_printk(KERN_WARNING, "File version is [%d]; only " |
|
"file version [%d] is supported by this " |
|
"version of eCryptfs\n", |
|
crypt_stat->file_version, |
|
ECRYPTFS_SUPPORTED_FILE_VERSION); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
offset += bytes_read; |
|
if (crypt_stat->file_version >= 1) { |
|
rc = parse_header_metadata(crypt_stat, (page_virt + offset), |
|
&bytes_read, validate_header_size); |
|
if (rc) { |
|
ecryptfs_printk(KERN_WARNING, "Error reading header " |
|
"metadata; rc = [%d]\n", rc); |
|
} |
|
offset += bytes_read; |
|
} else |
|
set_default_header_data(crypt_stat); |
|
rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset), |
|
ecryptfs_dentry); |
|
out: |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_read_xattr_region |
|
* @page_virt: The vitual address into which to read the xattr data |
|
* @ecryptfs_inode: The eCryptfs inode |
|
* |
|
* Attempts to read the crypto metadata from the extended attribute |
|
* region of the lower file. |
|
* |
|
* Returns zero on success; non-zero on error |
|
*/ |
|
int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode) |
|
{ |
|
struct dentry *lower_dentry = |
|
ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry; |
|
ssize_t size; |
|
int rc = 0; |
|
|
|
size = ecryptfs_getxattr_lower(lower_dentry, |
|
ecryptfs_inode_to_lower(ecryptfs_inode), |
|
ECRYPTFS_XATTR_NAME, |
|
page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE); |
|
if (size < 0) { |
|
if (unlikely(ecryptfs_verbosity > 0)) |
|
printk(KERN_INFO "Error attempting to read the [%s] " |
|
"xattr from the lower file; return value = " |
|
"[%zd]\n", ECRYPTFS_XATTR_NAME, size); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
out: |
|
return rc; |
|
} |
|
|
|
int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry, |
|
struct inode *inode) |
|
{ |
|
u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
|
u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; |
|
int rc; |
|
|
|
rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), |
|
ecryptfs_inode_to_lower(inode), |
|
ECRYPTFS_XATTR_NAME, file_size, |
|
ECRYPTFS_SIZE_AND_MARKER_BYTES); |
|
if (rc < 0) |
|
return rc; |
|
else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) |
|
return -EINVAL; |
|
rc = ecryptfs_validate_marker(marker); |
|
if (!rc) |
|
ecryptfs_i_size_init(file_size, inode); |
|
return rc; |
|
} |
|
|
|
/* |
|
* ecryptfs_read_metadata |
|
* |
|
* Common entry point for reading file metadata. From here, we could |
|
* retrieve the header information from the header region of the file, |
|
* the xattr region of the file, or some other repository that is |
|
* stored separately from the file itself. The current implementation |
|
* supports retrieving the metadata information from the file contents |
|
* and from the xattr region. |
|
* |
|
* Returns zero if valid headers found and parsed; non-zero otherwise |
|
*/ |
|
int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry) |
|
{ |
|
int rc; |
|
char *page_virt; |
|
struct inode *ecryptfs_inode = d_inode(ecryptfs_dentry); |
|
struct ecryptfs_crypt_stat *crypt_stat = |
|
&ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
|
&ecryptfs_superblock_to_private( |
|
ecryptfs_dentry->d_sb)->mount_crypt_stat; |
|
|
|
ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
|
mount_crypt_stat); |
|
/* Read the first page from the underlying file */ |
|
page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER); |
|
if (!page_virt) { |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size, |
|
ecryptfs_inode); |
|
if (rc >= 0) |
|
rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, |
|
ecryptfs_dentry, |
|
ECRYPTFS_VALIDATE_HEADER_SIZE); |
|
if (rc) { |
|
/* metadata is not in the file header, so try xattrs */ |
|
memset(page_virt, 0, PAGE_SIZE); |
|
rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode); |
|
if (rc) { |
|
printk(KERN_DEBUG "Valid eCryptfs headers not found in " |
|
"file header region or xattr region, inode %lu\n", |
|
ecryptfs_inode->i_ino); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, |
|
ecryptfs_dentry, |
|
ECRYPTFS_DONT_VALIDATE_HEADER_SIZE); |
|
if (rc) { |
|
printk(KERN_DEBUG "Valid eCryptfs headers not found in " |
|
"file xattr region either, inode %lu\n", |
|
ecryptfs_inode->i_ino); |
|
rc = -EINVAL; |
|
} |
|
if (crypt_stat->mount_crypt_stat->flags |
|
& ECRYPTFS_XATTR_METADATA_ENABLED) { |
|
crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; |
|
} else { |
|
printk(KERN_WARNING "Attempt to access file with " |
|
"crypto metadata only in the extended attribute " |
|
"region, but eCryptfs was mounted without " |
|
"xattr support enabled. eCryptfs will not treat " |
|
"this like an encrypted file, inode %lu\n", |
|
ecryptfs_inode->i_ino); |
|
rc = -EINVAL; |
|
} |
|
} |
|
out: |
|
if (page_virt) { |
|
memset(page_virt, 0, PAGE_SIZE); |
|
kmem_cache_free(ecryptfs_header_cache, page_virt); |
|
} |
|
return rc; |
|
} |
|
|
|
/* |
|
* ecryptfs_encrypt_filename - encrypt filename |
|
* |
|
* CBC-encrypts the filename. We do not want to encrypt the same |
|
* filename with the same key and IV, which may happen with hard |
|
* links, so we prepend random bits to each filename. |
|
* |
|
* Returns zero on success; non-zero otherwise |
|
*/ |
|
static int |
|
ecryptfs_encrypt_filename(struct ecryptfs_filename *filename, |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
|
{ |
|
int rc = 0; |
|
|
|
filename->encrypted_filename = NULL; |
|
filename->encrypted_filename_size = 0; |
|
if (mount_crypt_stat && (mount_crypt_stat->flags |
|
& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) { |
|
size_t packet_size; |
|
size_t remaining_bytes; |
|
|
|
rc = ecryptfs_write_tag_70_packet( |
|
NULL, NULL, |
|
&filename->encrypted_filename_size, |
|
mount_crypt_stat, NULL, |
|
filename->filename_size); |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error attempting to get packet " |
|
"size for tag 72; rc = [%d]\n", __func__, |
|
rc); |
|
filename->encrypted_filename_size = 0; |
|
goto out; |
|
} |
|
filename->encrypted_filename = |
|
kmalloc(filename->encrypted_filename_size, GFP_KERNEL); |
|
if (!filename->encrypted_filename) { |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
remaining_bytes = filename->encrypted_filename_size; |
|
rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename, |
|
&remaining_bytes, |
|
&packet_size, |
|
mount_crypt_stat, |
|
filename->filename, |
|
filename->filename_size); |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error attempting to generate " |
|
"tag 70 packet; rc = [%d]\n", __func__, |
|
rc); |
|
kfree(filename->encrypted_filename); |
|
filename->encrypted_filename = NULL; |
|
filename->encrypted_filename_size = 0; |
|
goto out; |
|
} |
|
filename->encrypted_filename_size = packet_size; |
|
} else { |
|
printk(KERN_ERR "%s: No support for requested filename " |
|
"encryption method in this release\n", __func__); |
|
rc = -EOPNOTSUPP; |
|
goto out; |
|
} |
|
out: |
|
return rc; |
|
} |
|
|
|
static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size, |
|
const char *name, size_t name_size) |
|
{ |
|
int rc = 0; |
|
|
|
(*copied_name) = kmalloc((name_size + 1), GFP_KERNEL); |
|
if (!(*copied_name)) { |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
memcpy((void *)(*copied_name), (void *)name, name_size); |
|
(*copied_name)[(name_size)] = '\0'; /* Only for convenience |
|
* in printing out the |
|
* string in debug |
|
* messages */ |
|
(*copied_name_size) = name_size; |
|
out: |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_process_key_cipher - Perform key cipher initialization. |
|
* @key_tfm: Crypto context for key material, set by this function |
|
* @cipher_name: Name of the cipher |
|
* @key_size: Size of the key in bytes |
|
* |
|
* Returns zero on success. Any crypto_tfm structs allocated here |
|
* should be released by other functions, such as on a superblock put |
|
* event, regardless of whether this function succeeds for fails. |
|
*/ |
|
static int |
|
ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm, |
|
char *cipher_name, size_t *key_size) |
|
{ |
|
char dummy_key[ECRYPTFS_MAX_KEY_BYTES]; |
|
char *full_alg_name = NULL; |
|
int rc; |
|
|
|
*key_tfm = NULL; |
|
if (*key_size > ECRYPTFS_MAX_KEY_BYTES) { |
|
rc = -EINVAL; |
|
printk(KERN_ERR "Requested key size is [%zd] bytes; maximum " |
|
"allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES); |
|
goto out; |
|
} |
|
rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name, |
|
"ecb"); |
|
if (rc) |
|
goto out; |
|
*key_tfm = crypto_alloc_skcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC); |
|
if (IS_ERR(*key_tfm)) { |
|
rc = PTR_ERR(*key_tfm); |
|
printk(KERN_ERR "Unable to allocate crypto cipher with name " |
|
"[%s]; rc = [%d]\n", full_alg_name, rc); |
|
goto out; |
|
} |
|
crypto_skcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); |
|
if (*key_size == 0) |
|
*key_size = crypto_skcipher_max_keysize(*key_tfm); |
|
get_random_bytes(dummy_key, *key_size); |
|
rc = crypto_skcipher_setkey(*key_tfm, dummy_key, *key_size); |
|
if (rc) { |
|
printk(KERN_ERR "Error attempting to set key of size [%zd] for " |
|
"cipher [%s]; rc = [%d]\n", *key_size, full_alg_name, |
|
rc); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
out: |
|
kfree(full_alg_name); |
|
return rc; |
|
} |
|
|
|
struct kmem_cache *ecryptfs_key_tfm_cache; |
|
static struct list_head key_tfm_list; |
|
DEFINE_MUTEX(key_tfm_list_mutex); |
|
|
|
int __init ecryptfs_init_crypto(void) |
|
{ |
|
INIT_LIST_HEAD(&key_tfm_list); |
|
return 0; |
|
} |
|
|
|
/** |
|
* ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list |
|
* |
|
* Called only at module unload time |
|
*/ |
|
int ecryptfs_destroy_crypto(void) |
|
{ |
|
struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp; |
|
|
|
mutex_lock(&key_tfm_list_mutex); |
|
list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list, |
|
key_tfm_list) { |
|
list_del(&key_tfm->key_tfm_list); |
|
crypto_free_skcipher(key_tfm->key_tfm); |
|
kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm); |
|
} |
|
mutex_unlock(&key_tfm_list_mutex); |
|
return 0; |
|
} |
|
|
|
int |
|
ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name, |
|
size_t key_size) |
|
{ |
|
struct ecryptfs_key_tfm *tmp_tfm; |
|
int rc = 0; |
|
|
|
BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); |
|
|
|
tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL); |
|
if (key_tfm) |
|
(*key_tfm) = tmp_tfm; |
|
if (!tmp_tfm) { |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
mutex_init(&tmp_tfm->key_tfm_mutex); |
|
strncpy(tmp_tfm->cipher_name, cipher_name, |
|
ECRYPTFS_MAX_CIPHER_NAME_SIZE); |
|
tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; |
|
tmp_tfm->key_size = key_size; |
|
rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm, |
|
tmp_tfm->cipher_name, |
|
&tmp_tfm->key_size); |
|
if (rc) { |
|
printk(KERN_ERR "Error attempting to initialize key TFM " |
|
"cipher with name = [%s]; rc = [%d]\n", |
|
tmp_tfm->cipher_name, rc); |
|
kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm); |
|
if (key_tfm) |
|
(*key_tfm) = NULL; |
|
goto out; |
|
} |
|
list_add(&tmp_tfm->key_tfm_list, &key_tfm_list); |
|
out: |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_tfm_exists - Search for existing tfm for cipher_name. |
|
* @cipher_name: the name of the cipher to search for |
|
* @key_tfm: set to corresponding tfm if found |
|
* |
|
* Searches for cached key_tfm matching @cipher_name |
|
* Must be called with &key_tfm_list_mutex held |
|
* Returns 1 if found, with @key_tfm set |
|
* Returns 0 if not found, with @key_tfm set to NULL |
|
*/ |
|
int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm) |
|
{ |
|
struct ecryptfs_key_tfm *tmp_key_tfm; |
|
|
|
BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); |
|
|
|
list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) { |
|
if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) { |
|
if (key_tfm) |
|
(*key_tfm) = tmp_key_tfm; |
|
return 1; |
|
} |
|
} |
|
if (key_tfm) |
|
(*key_tfm) = NULL; |
|
return 0; |
|
} |
|
|
|
/** |
|
* ecryptfs_get_tfm_and_mutex_for_cipher_name |
|
* |
|
* @tfm: set to cached tfm found, or new tfm created |
|
* @tfm_mutex: set to mutex for cached tfm found, or new tfm created |
|
* @cipher_name: the name of the cipher to search for and/or add |
|
* |
|
* Sets pointers to @tfm & @tfm_mutex matching @cipher_name. |
|
* Searches for cached item first, and creates new if not found. |
|
* Returns 0 on success, non-zero if adding new cipher failed |
|
*/ |
|
int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm, |
|
struct mutex **tfm_mutex, |
|
char *cipher_name) |
|
{ |
|
struct ecryptfs_key_tfm *key_tfm; |
|
int rc = 0; |
|
|
|
(*tfm) = NULL; |
|
(*tfm_mutex) = NULL; |
|
|
|
mutex_lock(&key_tfm_list_mutex); |
|
if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) { |
|
rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0); |
|
if (rc) { |
|
printk(KERN_ERR "Error adding new key_tfm to list; " |
|
"rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
} |
|
(*tfm) = key_tfm->key_tfm; |
|
(*tfm_mutex) = &key_tfm->key_tfm_mutex; |
|
out: |
|
mutex_unlock(&key_tfm_list_mutex); |
|
return rc; |
|
} |
|
|
|
/* 64 characters forming a 6-bit target field */ |
|
static unsigned char *portable_filename_chars = ("-.0123456789ABCD" |
|
"EFGHIJKLMNOPQRST" |
|
"UVWXYZabcdefghij" |
|
"klmnopqrstuvwxyz"); |
|
|
|
/* We could either offset on every reverse map or just pad some 0x00's |
|
* at the front here */ |
|
static const unsigned char filename_rev_map[256] = { |
|
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */ |
|
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */ |
|
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */ |
|
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */ |
|
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */ |
|
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */ |
|
0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */ |
|
0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */ |
|
0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */ |
|
0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */ |
|
0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */ |
|
0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */ |
|
0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */ |
|
0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */ |
|
0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */ |
|
0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */ |
|
}; |
|
|
|
/** |
|
* ecryptfs_encode_for_filename |
|
* @dst: Destination location for encoded filename |
|
* @dst_size: Size of the encoded filename in bytes |
|
* @src: Source location for the filename to encode |
|
* @src_size: Size of the source in bytes |
|
*/ |
|
static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size, |
|
unsigned char *src, size_t src_size) |
|
{ |
|
size_t num_blocks; |
|
size_t block_num = 0; |
|
size_t dst_offset = 0; |
|
unsigned char last_block[3]; |
|
|
|
if (src_size == 0) { |
|
(*dst_size) = 0; |
|
goto out; |
|
} |
|
num_blocks = (src_size / 3); |
|
if ((src_size % 3) == 0) { |
|
memcpy(last_block, (&src[src_size - 3]), 3); |
|
} else { |
|
num_blocks++; |
|
last_block[2] = 0x00; |
|
switch (src_size % 3) { |
|
case 1: |
|
last_block[0] = src[src_size - 1]; |
|
last_block[1] = 0x00; |
|
break; |
|
case 2: |
|
last_block[0] = src[src_size - 2]; |
|
last_block[1] = src[src_size - 1]; |
|
} |
|
} |
|
(*dst_size) = (num_blocks * 4); |
|
if (!dst) |
|
goto out; |
|
while (block_num < num_blocks) { |
|
unsigned char *src_block; |
|
unsigned char dst_block[4]; |
|
|
|
if (block_num == (num_blocks - 1)) |
|
src_block = last_block; |
|
else |
|
src_block = &src[block_num * 3]; |
|
dst_block[0] = ((src_block[0] >> 2) & 0x3F); |
|
dst_block[1] = (((src_block[0] << 4) & 0x30) |
|
| ((src_block[1] >> 4) & 0x0F)); |
|
dst_block[2] = (((src_block[1] << 2) & 0x3C) |
|
| ((src_block[2] >> 6) & 0x03)); |
|
dst_block[3] = (src_block[2] & 0x3F); |
|
dst[dst_offset++] = portable_filename_chars[dst_block[0]]; |
|
dst[dst_offset++] = portable_filename_chars[dst_block[1]]; |
|
dst[dst_offset++] = portable_filename_chars[dst_block[2]]; |
|
dst[dst_offset++] = portable_filename_chars[dst_block[3]]; |
|
block_num++; |
|
} |
|
out: |
|
return; |
|
} |
|
|
|
static size_t ecryptfs_max_decoded_size(size_t encoded_size) |
|
{ |
|
/* Not exact; conservatively long. Every block of 4 |
|
* encoded characters decodes into a block of 3 |
|
* decoded characters. This segment of code provides |
|
* the caller with the maximum amount of allocated |
|
* space that @dst will need to point to in a |
|
* subsequent call. */ |
|
return ((encoded_size + 1) * 3) / 4; |
|
} |
|
|
|
/** |
|
* ecryptfs_decode_from_filename |
|
* @dst: If NULL, this function only sets @dst_size and returns. If |
|
* non-NULL, this function decodes the encoded octets in @src |
|
* into the memory that @dst points to. |
|
* @dst_size: Set to the size of the decoded string. |
|
* @src: The encoded set of octets to decode. |
|
* @src_size: The size of the encoded set of octets to decode. |
|
*/ |
|
static void |
|
ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size, |
|
const unsigned char *src, size_t src_size) |
|
{ |
|
u8 current_bit_offset = 0; |
|
size_t src_byte_offset = 0; |
|
size_t dst_byte_offset = 0; |
|
|
|
if (!dst) { |
|
(*dst_size) = ecryptfs_max_decoded_size(src_size); |
|
goto out; |
|
} |
|
while (src_byte_offset < src_size) { |
|
unsigned char src_byte = |
|
filename_rev_map[(int)src[src_byte_offset]]; |
|
|
|
switch (current_bit_offset) { |
|
case 0: |
|
dst[dst_byte_offset] = (src_byte << 2); |
|
current_bit_offset = 6; |
|
break; |
|
case 6: |
|
dst[dst_byte_offset++] |= (src_byte >> 4); |
|
dst[dst_byte_offset] = ((src_byte & 0xF) |
|
<< 4); |
|
current_bit_offset = 4; |
|
break; |
|
case 4: |
|
dst[dst_byte_offset++] |= (src_byte >> 2); |
|
dst[dst_byte_offset] = (src_byte << 6); |
|
current_bit_offset = 2; |
|
break; |
|
case 2: |
|
dst[dst_byte_offset++] |= (src_byte); |
|
current_bit_offset = 0; |
|
break; |
|
} |
|
src_byte_offset++; |
|
} |
|
(*dst_size) = dst_byte_offset; |
|
out: |
|
return; |
|
} |
|
|
|
/** |
|
* ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text |
|
* @encoded_name: The encrypted name |
|
* @encoded_name_size: Length of the encrypted name |
|
* @mount_crypt_stat: The crypt_stat struct associated with the file name to encode |
|
* @name: The plaintext name |
|
* @name_size: The length of the plaintext name |
|
* |
|
* Encrypts and encodes a filename into something that constitutes a |
|
* valid filename for a filesystem, with printable characters. |
|
* |
|
* We assume that we have a properly initialized crypto context, |
|
* pointed to by crypt_stat->tfm. |
|
* |
|
* Returns zero on success; non-zero on otherwise |
|
*/ |
|
int ecryptfs_encrypt_and_encode_filename( |
|
char **encoded_name, |
|
size_t *encoded_name_size, |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat, |
|
const char *name, size_t name_size) |
|
{ |
|
size_t encoded_name_no_prefix_size; |
|
int rc = 0; |
|
|
|
(*encoded_name) = NULL; |
|
(*encoded_name_size) = 0; |
|
if (mount_crypt_stat && (mount_crypt_stat->flags |
|
& ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { |
|
struct ecryptfs_filename *filename; |
|
|
|
filename = kzalloc(sizeof(*filename), GFP_KERNEL); |
|
if (!filename) { |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
filename->filename = (char *)name; |
|
filename->filename_size = name_size; |
|
rc = ecryptfs_encrypt_filename(filename, mount_crypt_stat); |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error attempting to encrypt " |
|
"filename; rc = [%d]\n", __func__, rc); |
|
kfree(filename); |
|
goto out; |
|
} |
|
ecryptfs_encode_for_filename( |
|
NULL, &encoded_name_no_prefix_size, |
|
filename->encrypted_filename, |
|
filename->encrypted_filename_size); |
|
if (mount_crypt_stat |
|
&& (mount_crypt_stat->flags |
|
& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) |
|
(*encoded_name_size) = |
|
(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE |
|
+ encoded_name_no_prefix_size); |
|
else |
|
(*encoded_name_size) = |
|
(ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE |
|
+ encoded_name_no_prefix_size); |
|
(*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL); |
|
if (!(*encoded_name)) { |
|
rc = -ENOMEM; |
|
kfree(filename->encrypted_filename); |
|
kfree(filename); |
|
goto out; |
|
} |
|
if (mount_crypt_stat |
|
&& (mount_crypt_stat->flags |
|
& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) { |
|
memcpy((*encoded_name), |
|
ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, |
|
ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE); |
|
ecryptfs_encode_for_filename( |
|
((*encoded_name) |
|
+ ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE), |
|
&encoded_name_no_prefix_size, |
|
filename->encrypted_filename, |
|
filename->encrypted_filename_size); |
|
(*encoded_name_size) = |
|
(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE |
|
+ encoded_name_no_prefix_size); |
|
(*encoded_name)[(*encoded_name_size)] = '\0'; |
|
} else { |
|
rc = -EOPNOTSUPP; |
|
} |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error attempting to encode " |
|
"encrypted filename; rc = [%d]\n", __func__, |
|
rc); |
|
kfree((*encoded_name)); |
|
(*encoded_name) = NULL; |
|
(*encoded_name_size) = 0; |
|
} |
|
kfree(filename->encrypted_filename); |
|
kfree(filename); |
|
} else { |
|
rc = ecryptfs_copy_filename(encoded_name, |
|
encoded_name_size, |
|
name, name_size); |
|
} |
|
out: |
|
return rc; |
|
} |
|
|
|
static bool is_dot_dotdot(const char *name, size_t name_size) |
|
{ |
|
if (name_size == 1 && name[0] == '.') |
|
return true; |
|
else if (name_size == 2 && name[0] == '.' && name[1] == '.') |
|
return true; |
|
|
|
return false; |
|
} |
|
|
|
/** |
|
* ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext |
|
* @plaintext_name: The plaintext name |
|
* @plaintext_name_size: The plaintext name size |
|
* @sb: Ecryptfs's super_block |
|
* @name: The filename in cipher text |
|
* @name_size: The cipher text name size |
|
* |
|
* Decrypts and decodes the filename. |
|
* |
|
* Returns zero on error; non-zero otherwise |
|
*/ |
|
int ecryptfs_decode_and_decrypt_filename(char **plaintext_name, |
|
size_t *plaintext_name_size, |
|
struct super_block *sb, |
|
const char *name, size_t name_size) |
|
{ |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
|
&ecryptfs_superblock_to_private(sb)->mount_crypt_stat; |
|
char *decoded_name; |
|
size_t decoded_name_size; |
|
size_t packet_size; |
|
int rc = 0; |
|
|
|
if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) && |
|
!(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)) { |
|
if (is_dot_dotdot(name, name_size)) { |
|
rc = ecryptfs_copy_filename(plaintext_name, |
|
plaintext_name_size, |
|
name, name_size); |
|
goto out; |
|
} |
|
|
|
if (name_size <= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE || |
|
strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, |
|
ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)) { |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
|
|
name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; |
|
name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; |
|
ecryptfs_decode_from_filename(NULL, &decoded_name_size, |
|
name, name_size); |
|
decoded_name = kmalloc(decoded_name_size, GFP_KERNEL); |
|
if (!decoded_name) { |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
ecryptfs_decode_from_filename(decoded_name, &decoded_name_size, |
|
name, name_size); |
|
rc = ecryptfs_parse_tag_70_packet(plaintext_name, |
|
plaintext_name_size, |
|
&packet_size, |
|
mount_crypt_stat, |
|
decoded_name, |
|
decoded_name_size); |
|
if (rc) { |
|
ecryptfs_printk(KERN_DEBUG, |
|
"%s: Could not parse tag 70 packet from filename\n", |
|
__func__); |
|
goto out_free; |
|
} |
|
} else { |
|
rc = ecryptfs_copy_filename(plaintext_name, |
|
plaintext_name_size, |
|
name, name_size); |
|
goto out; |
|
} |
|
out_free: |
|
kfree(decoded_name); |
|
out: |
|
return rc; |
|
} |
|
|
|
#define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143 |
|
|
|
int ecryptfs_set_f_namelen(long *namelen, long lower_namelen, |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
|
{ |
|
struct crypto_skcipher *tfm; |
|
struct mutex *tfm_mutex; |
|
size_t cipher_blocksize; |
|
int rc; |
|
|
|
if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { |
|
(*namelen) = lower_namelen; |
|
return 0; |
|
} |
|
|
|
rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, |
|
mount_crypt_stat->global_default_fn_cipher_name); |
|
if (unlikely(rc)) { |
|
(*namelen) = 0; |
|
return rc; |
|
} |
|
|
|
mutex_lock(tfm_mutex); |
|
cipher_blocksize = crypto_skcipher_blocksize(tfm); |
|
mutex_unlock(tfm_mutex); |
|
|
|
/* Return an exact amount for the common cases */ |
|
if (lower_namelen == NAME_MAX |
|
&& (cipher_blocksize == 8 || cipher_blocksize == 16)) { |
|
(*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16; |
|
return 0; |
|
} |
|
|
|
/* Return a safe estimate for the uncommon cases */ |
|
(*namelen) = lower_namelen; |
|
(*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; |
|
/* Since this is the max decoded size, subtract 1 "decoded block" len */ |
|
(*namelen) = ecryptfs_max_decoded_size(*namelen) - 3; |
|
(*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE; |
|
(*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES; |
|
/* Worst case is that the filename is padded nearly a full block size */ |
|
(*namelen) -= cipher_blocksize - 1; |
|
|
|
if ((*namelen) < 0) |
|
(*namelen) = 0; |
|
|
|
return 0; |
|
}
|
|
|